1.Given three resistors, how many different combinations of these three resistors can be made?
a) 3         b) 4         c) 5         d) 6

2.Three resistors of 4Ω, 6Ω and 12Ω are connected in parallel and the combination is connected in series with 4V battery with internal resistance of 2Ω. The battery current is
a) 0.5 A         b) 1A         c) 2 A         d) 10 A

3.The appropriate material to be used in the construction of resistance boxes is
a) copper         b) iron         c) maganin         d) aluminium

4.Two cells of 1.25V and 0.75V are connected in parallel. The effectice voltage will be
a) 0.75 V         b) 1.25 V         c) 2 V         d) 0.5 V

5.When a current flows in a conductor, the order of magnitude of drift velocity of electrons through it is
a) 10−7cm/s         b) 10−2cm/s             c) 104cm/s         d) 1010cm/s

6.Ampere Hour is the unit of
a) quantity of charge 
b) strength of current 
c) power 
d) energy

7.The conductivity of a super conductor is
a) infinite             b) very large         c) very small         d) zero

8.Wheatstone Bridge is used to measure
a) emf         b) potential         c) resistance         d) current

9.The potential gradiant along the length uniform wire is 10 v/m. The length of wire is 1m. What is the p.d across two points on the wire seperated by 25cm?
a) 2.5V         b) 5V         c) 7.5V         d) 10V
10.A primary cell has an emf of 1.5E .When short circuited it gives a current of 3A. The internal rsistance of the cell is
a) 4.5 ohm         b) 2 ohm         c) 0.5 ohm         d) 14.5ohm

11.The smallest resistance that can be obtained by the combination of 'n' resistors each of resistance R is
a) R/n2         b) R/n         c) nR     d) n2R

12.The resistance of a wire is R. It is uniformely streached to n times, its length. The resistance now will be
a) R         b) nR         c) n2R         d) R/n

13.A certain piece of copper is to be shaped into a wire of minimum resistance. Its length and diameter should be
a) L, D         b) 2L,D         c) L/2, 2D         d) 2L, D/2

14.The capacity of storage cell is 2.5Ah. What is the maximum current that it can supply for half an hour?
a) 0.5A         b) 1A         c) 2.5 A         d) 5 A

15.The specific resistance of a wire 1.1m long 0.4mm in diameter and having a total resistance of 4.2 ohm will be
a) 4.97×105Ωm 
b) 48×10−8Ωm 
c) 48×104Ωm 
d) 48×103Ωm

16.Chose the wrong statement. Sensitivity of a galvanometer is increased by
a) increasing number of turns 
b) increasing the strength of field 
c) inserting soft iron cylinder inside the coil 
d) using suspension fibre of high restoring couple

17.A given cyclotrone can be used to produce high energy in
a) α-particles 
b) β-particles 
c) γ- rays 
d) hydrogen atom

18.An electron beam is deflected in a given field. The nature of this uniform field can be obtained as
a) axial magnetic field if path is circular 
b) transverse electric field if path is straight line 
c) electric if path is parabola and magnetic if path is circular 
d) magnetic if path of beam is parabola

19.A straight horizontal conducting rod of length 0.5m and 0.1 kg is suspended by two vertical wires at its ends. A current of 10A flows through the rod. The magnetic field set up normal to the wire so that the tension in the wire is zero is
a) 1.96T 
b) 0.196T 
c) 1.96×103T 
d) 19.6 T

20.A cyclotron in which the magnetic field is 1.4 T is used to accelerate protons. How rapidly should the electric field between the dees be reversed?
a) 2.343×10−8s 
b) 2.343×10−7s 
c) 2.343×10−6s 
d) 2.343×10−9s

21.A galvanometer has a resistance of 5 ohm and a full scale deflection is produced by 15mA. The resistance required to read 1.5V is
a) 9×10−3Ω 
b) 9×10+3Ω 
c) 0.95Ω 
d) 95Ω

22.A moving coil galvanometer of resistance 10Ω gives a full scale deflection for a current of 15mA, the shunt required to obtain an ammeter to measure 3A current
a) 5 ohm         b) 0.5 ohm         c) 2.5 ohm         d) 0.05 ohm

23.A circular coil of wire of 50 turns and radius 0.05m carries a current of 1A. The wire is suspended vertically in a uniform magnetic field of strngth 1.5 T. Direction of magnetric field is parallel to the plane of the coil. The torque on the coil is
a) 0.589 J         b) 0.859 J         c) 0.958 J         d) 5.89 J

24.A solenoid has mean diameter of 0.05m and length 2m. It has 4 layers of 1000 turns each and a current of 2.5A flows through it. The magnetic field at a point on the axis neat its one end is
a) 3.14×103T 
b) 3.14×103T 
c) 3.14×10−4T 
d) 3.14×10−3T

25.Two straight wires each one meter long are parallel to one another and are each carrying a current of 40A in the same direction. The force between the wires if the distance between the wires is 0.02m is
a) 8×10−3N , attractive 
b) 8×10−3N , repulsive 
c) 16×10−3N , repulsive 
d) 16×10−3N, attractive

26.The force acting on a wire of length 0.05m placed inside a long solenoid near its centre making an angle of 300with the axis of the solenoid, if the wire carries a current of 10A and magnetic field due to the solenoid is 0.2T is
a) 0.5N         b) 0.05 N         c) 0.005 N         d) 5N

27.A horizontal overhead power line carries a current of 100A from east to west. The magnetic field at point 5m below the line is
a) 4×10−6T, towards north 
b) 4×106T, towards south 
c) 40×106T, towards north 
d) 4×10−6T, towards south

28.A circular coil of 20 turns and radius 10 cm is placed in a uniform magnetic field of 0.01T normal to the plane of the coil. If the current in the coil is 5A, the force and torque acting on it are respectively
a) F=0,τ=7.85×10−3Nm 
b) F=0,τ=0.0157Nm 
c) τ=0,F=0.0157N 
d) F=0,τ=0

29.A wire of certain length carries a steady current. It is first bent to form a circular coil of 1 turn. The same wire is next bent to form a circular coil of 3 turns. The ratio of magnetic induction at the centre of the coil in the two cases is
a) 9:1         b) 1:9         c) 1:3         d) 3:1

30.Two long stright parallel conductors seperated by a distance of 0.5m carry currents of 5A and 8A in the same direction. The force per unit length experienced by each other is
a) 1.6×10−5N(attractive) 
b) 1.6×10−5N (repulsive) 
c) 16×10−5N(attractive) 
d) 16×10−5N (repulsive)

31.A current carrying loop is placed in a uniform magnetic field. The torque acting on it does not depend on
a) shape of the loop 
b) area of the loop 
c) number of turns in the loop 
d) strength of the current

32.The force on a conductor of length l placed in a magnetic field of magnitude B and carrying a current I is given by (θ is the angle the conductor makes with the direction of B)
a) F = IlB sin θ 
b) F=I2lB2sinθ 
c) F=IlBcosθ 
d) F=I2lsinθ/B

33.A solenoid of length 50 cm and a radius of cross section 1cm has 1000 turns of wire wound over it. If the current carried is 5A, the magnetic field on its axis, near the centre of the solenoid is approximately (permeability of free space, μ0=4π×10−7Tm/A)
a) 0.6×10−2T 
b) 1.26×10−2T 
c) 2.51×10−2T 
d) 6.3×10−2T

34.A charged particle travels along a straight line with a speed v in a region where both electric field E and magnetic fields B are present. It follows that
a) E = vB and the two fields are parallel 
b) E = vB and the two fields are perpendicular 
c) B = vE and the two fields are parallel 
d) B = vE and the two fields are perpendicular

35.Two thin long parallel wires seperated by a distance d carry current 'i' amperes each. The magnitude of the force per unit length exerted by one wire on the the other is
a) μ0i2/2πd             b) μ0i2/2πd             c) μ0i/2πd             d) μ0i/4πd

36.Two galvanometers A and B require 3 mA and 5 mA respectively to produce the same deflection of 10 divisions. Then
a) A is more sensitive than B 
b) B is more sensitive than A 
c) A and B are equally sensitive 
d) sensitiveness of B is twice that of A

37.A stright conductor carries a current of 5A. An electron travelling with a speed of 5×106m/s parallel to the wire at a distance of 0.1m from the conductor , experiences a force of
a) 8×10−20N 
b) 3.2×10−19N 
c) 8×10−18N 
d) 1.6×10−19N

38.The magnetic field at a point P which is at a distance of 4cm from a long current carrying conductor is 10−3T . The magnetic field at a distance of 12cm from the conductor is
a) 3.33×10−4T 
b) 3.33×10−3T 
c) 6.5×10−3T 
d) 2.5×10−8T

39.Two identical coins carry equal currents and have common centre but the planes of the coils are at right angles to each other. What is the magnitude of the resultant magnetic field at the centre if the field due to one coil alone is 'B'?
a) zero 
b) B/2 
c) 2B 
d) 2B

40.A charged particle in a magnetic field experiences maximum force when,
a) it is moving in a direction parallel to the field 
b) It is at rest 
c) it is moving in a direction perpendicular to the field 
d) it is moving at an angle 450to the direction of the field

41.A wire of length L metre carrying a current 'i' ampere is bent in the form of a circle. The magnitude of magnetic moment is
a) iL2/4π         b) iL2/2π         c) 4π2L2i         d) πL2i

42.The force existing between two current carrying conductors is 'F'. If the current in each conductor doubled then the value of force will be
a) 4F         b) 3F         c) 2F         d) F

43.The frequency of an electron circulating at right angles to a uniform magnetic field does not depend upon
a) speed of the charge 
b) mass of the charge 
c) charge of the particle 
d) magnetic field 'B'

44.The dimensions of magnetic field intensity 'B' is
a) MLT−2I−1 b) MLT−1I−1 c) MT−1I−1 d) ML2T2

45.Which of the following represent 'tesla'?
a) NsC−1 
b) Ns−1C−1m−1 
c) Ns−2C−1m 
d) NsC−1m−1

46.A current carrying loop is free to turn in a uniform magnetic field. The loop will then come into equilibrium when its plane is inclined at (w.r to direction of field)
a) 00             b) 450         c) 1350             d) 900

47.An electron of charge 1.6×10−19C and mass 1.0×10−30kg moves in a circular orbit with a speed of 5.0×106m/s, under the influence of a magnetic flux density 2.0×10−2T. What forces does it experience?
a) 1.66×10−44N 
b) 1.66×10−14N 
c) 3.2×10−24J 
d) 6.4×10−28N

48.An alpha particle and a beta particle are moving with equal velocities perpendicular to the direction of uniform magnetic field the magnitude of forces due to the field acting on each of them
a) are the same 
b) differ by a factor of 2 
c) differ by a factor of 4 
d) differ by a factor of 6

49.An horizontal wire carries a current east to west. The direction of magnetic field set up by the current at a point directly above the wire is towards
a) north         b) south         c) east         d) west

50.The current flowing through a galvanometer of resitance 500 ohms is to be reduced by 80%, what is the value of shunt resistance to be connected? Assume that total current remains constant
a) 125 ohm         b) 12.5 ohm         c) 500 ohm         d) 50 ohm